Explanation: Our solar system's miasma of incandescent plasma, the Sun may look a little scary here. The picture is a composite of 25 images recorded in extreme ultraviolet light by the orbiting Solar Dynamics Observatory between April 16, 2012 and April 15, 2013. The particular wavelength of light, 171 angstroms, shows emission from highly ionized iron atoms in the solar corona at a characteristic temperatures of about 600,000 kelvins (about 1 million degrees F). Girdling both sides of the equator during the approach to maximum in its 11-year solar cycle, the solar active regions are laced with bright loops and arcs along magnetic field lines. Of course, a more familiar visible light view would show the bright active regions as groups of dark sunspots. Three years of Solar Dynamics Observatory images are compressed into this short video.

Actually the surface is about 5,800 K. It’s in the outer atmosphere that the temperature rises to almost a million degrees. I was confused about that for a time, but the outer atmosphere is rarified gas, and although the atoms absorb enough high-energy light to get that hot, per volume the heat is actually less. Heat conduction is more difficult when atoms are separated, which is why they get hotter individually.

11
posted on 04/25/2013 11:49:55 PM PDT
by Telepathic Intruder
(The only thing the Left has learned from the failures of socialism is not to call it that)

Iron is where fission and fusion meet, so, under the current consensus model, yes. :’) Eventually everything winds up iron, and that’s the end of energy production (and life). However, in the meantime, Earth et al is made of iron and other heavier elements produced by stars, and we, uh, need Earth.

[snip] In a short chapter entitled “The Relative Abundance of the Elements there is a ticking time bomb. This is the extremely high abundance of hydrogen and helium that had come out under certain assumptions in the analysis. Although we know today that this high abundance is real, at the time it produced an apparent anomaly with respect to the assumed homogeneity of the solar system. After all, when the earth is taken as a whole, it must be predominately iron in order to account for its high mean density, and this is supported by the fact that meteorites are largely iron and by the appearance of the solar spectrum itself, which shows more lines of iron than any other element. The very important principle of uniformity of nature seemed at stake. As Cecilia herself argued in her thesis, “If . . . the earth originated from the surface layers of the sun, the percentage composition of the whole earth should resemble the composition of the solar (and therefore of a typical stellar) atmosphere. . . . Considering the possibility of atomic segregation both in the earth and in the star, it appears likely that the earths crust is representative of the stellar atmosphere.” [/snip]

14
posted on 04/26/2013 7:46:03 PM PDT
by SunkenCiv
(Romney would have been worse, if you're a dumb ass.)

That's largely correct. The key to understanding it is the nuclear binding energy curve: which is the excess energy needed to keep an atom stable. Iron represents the bottom of the curve (or the top in this case). Energy is released by combining atoms lighter than iron, and by splitting atoms that are heavier. When a star fuses elements up to iron, no more energy can be attained from fusion. The equilibrium between gravitational collapse and thermal expansion is broken, and the core collapses. This is actually a fascinating event. About as much energy is released in 10 seconds as our sun will produce in its entire 10 billion year life span. And that's from an area only 20 miles across.

19
posted on 04/27/2013 9:54:20 AM PDT
by Telepathic Intruder
(The only thing the Left has learned from the failures of socialism is not to call it that)

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